U.S. patent number 6,754,048 [Application Number 09/920,602] was granted by the patent office on 2004-06-22 for multiple magnetoresistive (mr) layer sensor element having longitudinal bias layers with non-parallel magnetizations.
This patent grant is currently assigned to Headway Technologies, Inc.. Invention is credited to Min Li, Simon H. Liao.
United States Patent |
6,754,048 |
Li , et al. |
June 22, 2004 |
Multiple magnetoresistive (MR) layer sensor element having
longitudinal bias layers with non-parallel magnetizations
Abstract
Within a method for forming a magnetoresistive (MR) sensor
element there is first provided a substrate. There is then formed
over the substrate a first magnetoresistive (MR) layer having
formed contacting the first magnetoresistive (MR) layer a
magnetically biased first magnetic bias layer biased in a first
magnetic bias direction with a first magnetic bias field strength.
There is also formed separated from the first magnetoresistive (MR)
layer by a spacer layer a second magnetoresistive (MR) layer having
formed contacting the second magnetoresistive (MR) layer a
magnetically un-biased second magnetic bias layer. There is then
biased through use of a first thermal annealing method employing a
first thermal annealing temperature, a first thermal annealing
exposure time and a first extrinsic magnetic bias field the
magnetically un-biased second magnetic bias layer to form a
magnetically biased second magnetic bias layer having a second
magnetic bias field strength in a second magnetic bias direction
non-parallel to the first magnetic bias direction while
simultaneously partially demagnetizing the magnetically biased
first magnetic bias layer to provide a partially demagnetized
magnetically biased first magnetic bias layer having a partially
demagnetized first magnetic bias field strength less than the first
magnetic bias field strength. Finally, there is then annealed
thermally through use of a second thermal annealing employing a
second thermal annealing temperature and a second thermal annealing
exposure time without a second magnetic bias field: (1) the
partially demagnetized magnetically biased first magnetic bias
layer layer to form a remagnetized partially demagnetized first
magnetic bias layer having a remagnetized partially demagnetized
first netic bias field strength greater than the partially
demagnetized first magnetic bias field strength; and (2) the
magnetically biased second magnetic bias layer to form a further
magnetically biased second magnetic bias layer having a further
magnetized second magnetic bias field strength greater than the
second magnetic bias field strength.
Inventors: |
Li; Min (Fremont, CA), Liao;
Simon H. (Fremont, CA) |
Assignee: |
Headway Technologies, Inc.
(Milpitas, CA)
|
Family
ID: |
23476213 |
Appl.
No.: |
09/920,602 |
Filed: |
August 2, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
374310 |
Aug 16, 1999 |
6295718 |
|
|
|
Current U.S.
Class: |
360/315;
360/327.3; 257/E43.006; G9B/5.135; G9B/5.114 |
Current CPC
Class: |
B82Y
10/00 (20130101); B82Y 40/00 (20130101); G01R
33/093 (20130101); G11B 5/3903 (20130101); G11B
5/3967 (20130101); H01F 10/3263 (20130101); H01F
10/3268 (20130101); H01F 41/304 (20130101); H01L
43/12 (20130101); C10M 103/02 (20130101); C10M
103/04 (20130101); C10M 103/06 (20130101); C10M
111/00 (20130101); C10M 125/00 (20130101); C10M
125/22 (20130101); B82Y 25/00 (20130101); Y10T
29/49034 (20150115); C10M 2201/0413 (20130101); G11B
5/3954 (20130101); G11B 5/465 (20130101); G11B
2005/0008 (20130101); G11B 2005/3996 (20130101); Y10T
29/49021 (20150115); Y10T 29/49036 (20150115); Y10T
29/49043 (20150115) |
Current International
Class: |
G11B
5/39 (20060101); G01R 33/06 (20060101); H01F
41/14 (20060101); H01L 43/00 (20060101); G01R
33/09 (20060101); H01F 41/30 (20060101); H01L
43/12 (20060101); H01F 10/00 (20060101); H01F
10/32 (20060101); G11B 5/465 (20060101); G11B
5/00 (20060101); G11B 005/39 () |
Field of
Search: |
;360/314,316,327.1-327.32 ;149/108
;438/3,48,104,720,722,381,171,210 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Heinz; A. J.
Attorney, Agent or Firm: Saile; George O. Ackerman; Stephen
B.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a division of patent application Ser. No. 09/374,310,
filing date Aug. 16, 1999 now U.S. Pat. No. 6,295,718, Method For
Fabricating A Non-Parallel Magnetically Biased Multiple
Magetoresistive (Mr) Layer Manetoresistive (Mr) Sensor Element,
assigned to the same assignee as the present invention.
This application is related to co-assigned applications: (1) Ser.
No. 09/182,761, filed Oct. 30, 1998, titled "Canted Longitudinal
Patterned Exchange Biased Dual-Stripe Magnetoresistive (DSMR)
Sensor Element and Method for Fabrication Thereof"; and (2) Ser.
No. 09/182,775, also filed Oct. 30, 1998, titled "Anti-Parallel
Longitudinal Patterned Exchange Biased Dual Stripe Magnetoresistive
(DSMR) Sensor Element and Method for Fabrication Thereof", the
teachings and citations from both of which related co-assigned
applications are incorporated herein fully by reference.
Claims
What is claimed is:
1. A multiple magnetoresistive (MR) layer magnetoresistive (MR)
sensor element comprising: a substrate; a patterned first
magnetoresistive (MR) layer formed over the substrate; a first
magnetic longitudinal bias layer formed contacting the patterned
first magnetoresistive (MR) layer, the first magnetic longitudinal
bias layer having a first magnetic bias direction; a patterned
second magnetoresistive (MR) layer separated from the patterned
first magnetoresistive (MR) layer by at least a non-magnetic spacer
layer; and a second magnetic longitudinal bias layer formed
contacting the patterned second magnetoresistive (MR) layer, the
second magnetic longitudinal bias layer having a second magnetic
bias direction, wherein: the first magnetic longitudinal bias layer
and the second magnetic longitudinal bias layer are formed of a
single magnetic bias material; the first magnetic bias direction
and the second magnetic bias direction are non-parallel and aligned
at an acute angle with a longitudinal axis along which said bias
layers are separated.
2. The multiple magnetoresistive (MR) layer magnetoresistive (MR)
sensor element of claim 1 wherein the multiple magnetoresistive
(MR) layer magnetoresistive (MR) sensor element is employed within
a magnetic head selected from the group consisting of merged
inductive magnetic magnetic write magnetoresistive (MR) read
magnetic heads, non-merged inductive magnetic write
magnetoresistive (MR) read magnetoresistive (MR) heads and
magnetoresistive (MR) read only heads.
3. A magnetic data storage enclosure having fabricated therein said
magnetic head of claim 2.
4. The multiple magnetoresistive (MR) layer magnetoresistive (MR)
sensor element of claim 1 wherein the single magnetic bias material
is selected from the group consisting of antiferromagnetic magnetic
bias materials and permanent magnet magnetic bias materials.
5. The multiple magnetoresistive (MR) layer magnetoresistive (MR)
sensor element of claim 1 wherein the multiple magnetoresistive
(MR) layer magnetoresistive (MR) sensor element is a dual spin
valve magnetoresistive (DSVMR) sensor element.
6. The multiple magnetoresistive (MR) layer magnetoresistive (MR)
sensor element of claim 1 wherein the multiple magnetoresistive
(MR) layer magnetoresistive (MR) sensor element is a dual stripe
magnetoresistive (DSMR) sensor element.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to methods for fabricating
magnetic sensor elements. More particularly, the present invention
relates to methods for fabricating non-parallel magnetically biased
multiple magnetoresistive (MR) layer magnetoresistive (MR) sensor
elements.
2. Description of the Related Art
The recent and continuing advances in computer and information
technology have been made possible not only by the correlating
advances in the functionality, reliability and speed of
semiconductor integrated circuits, but also by the correlating
advances in the storage density and reliability of direct access
storage devices (DASDs) employed in digitally encoded magnetic data
storage and retrieval.
Storage density of direct access storage devices (DASDs) is
typically determined as areal storage density of a magnetic data
storage medium formed upon a rotating magnetic data storage disk
within a direct access storage device (DASD) magnetic data storage
enclosure. The areal storage density of the magnetic data storage
medium is defined largely by the track width, the track spacing and
the linear magnetic domain density within the magnetic data storage
medium. The track width, the track spacing and the linear magnetic
domain density within the magnetic data storage medium are in turn
determined by several principal factors, including but not limited
to: (1) the magnetic read-write characteristics of a magnetic
read-write head employed in reading and writing digitally encoded
magnetic data from and into the magnetic data storage medium; (2)
the magnetic domain characteristics of the magnetic data storage
medium; and (3) the separation distance of the magnetic read-write
head from the magnetic data storage medium.
With regard to the magnetic read-write characteristics of magnetic
read-write heads employed in reading and writing digitally encoded
magnetic data from and into a magnetic data storage medium, it is
known in the art of magnetic read-write head fabrication that
magnetoresistive (MR) sensor elements employed within
magnetoresistive (MR) read-write heads are generally superior to
other types of magnetic sensor elements when employed in retrieving
digitally encoded magnetic data from a magnetic data storage
medium. In that regard, magnetoresistive (MR) sensor elements are
generally regarded as superior since magnetoresistive (MR) sensor
elements are known in the art to provide high output digital read
signal amplitudes, with good linear resolution, independent of the
relative velocity of a magnetic data storage medium with respect to
a magnetoresistive (MR) read-write head having the magnetoresistive
(MR) sensor element incorporated therein.
Within the general category of magnetoresistive (MR) sensor
elements, magnetoresistive (MR) sensor elements which employ
multiple magnetoresistive (MR) layers (typically including a pair
of magnetoresistive (MR) layers), such as but not limited to dual
stripe magnetoresistive (DSMR) sensor elements and spin valve
magnetoresistive (DSVMR) sensor elements, and in particular
magnetoresistive (MR) sensor elements which employ multiple
magnetoresistive (MR) layers at least one of which is magnetically
biased to provide non-parallel magnetic bias directions of the
multiple magnetoresistive (MR) layer magnetoresistive (MR) sensor
elements, such as nominally anti-parallel longitudinally
magnetically biased dual stripe magnetoresistive (DSMR) sensor
elements and nominally perpendicularly magnetically biased spin
valve magnetoresistive (DSVMR) sensor elements, are presently of
considerable interest insofar as the magnetically biased
magnetoresistive (MR) layers employed within such magnetically
biased multiple magnetoresistive (MR) layer magnetoresistive (MR)
sensor elements typically provide enhanced magnetic read signal
amplitude and fidelity in comparison with single stripe
magnetoresistive (MR) sensor elements, non-magnetically biased
multiple magnetoresistive (MR) layer magnetoresistive (MR) sensor
elements and parallel magnetically biased multiple magnetoresistive
(MR) layer magnetoresistive (MR) sensor elements.
While non-parallel magnetically biased multiple magnetoresistive
(R) layer magnetoresistive (MR) sensor elements such as but not
limited to non-parallel longitudinally magnetically biased dual
stripe magnetoresistive (DSMR) sensor elements and non-parallel
perpendicularly magnetically biased dual spin valve
magnetoresistive (DSVMR) sensor elements are thus desirable within
the art of digitally encoded magnetic data storage and retrieval,
non-parallel multiple magnetoresistive (MR) layer magnetoresistive
(MR) sensor elements are nonetheless not fabricated entirely
without problems in the art of magnetoresistive (MR) sensor element
fabrication. In particular, as a data track width within a magnetic
medium employed within digitally encoded magnetic data storage and
retrieval decreases, it becomes increasingly important that a read
track width within a non-parallel magnetically biased multiple
magnetoresistive (MR) layer magnetoresistive (MR) sensor element
employed in reading the data within the data track be uniformly
magnetically biased (i.e. have a uniform cross-track magnetic bias
profile). Uniform cross-track magnetic bias profiles are desirable
within read track widths of non-parallel magnetically biased
multiple magnetoresistive (MR) layer magnetoresistive (MR) sensor
elements since such uniform cross-track magnetic bias profiles
provide for optimal magnetic read signal amplitudes within such
non-parallel magnetically biased multiple magnetoresistive (MR)
layer magnetoresistive (MR) sensor elements.
It is thus towards the goal of providing, for use within magnetic
data storage and retrieval, a method for forming a non-parallel
magnetically biased multiple magnetoresistive (MR) layer
magnetoresistive (MR) sensor element with a uniform cross-track
magnetic bias profile across a read track width of the non-parallel
magnetically biased multiple magnetoresistive (MR) layer
magnetoresistive (MR) sensor element, as well as a non-parallel
magnetically biased multiple magnetoresistive (MR) layer
magnetoresistive (MR) sensor element formed in accord with the
method, that the present invention is most generally directed.
Various methods and resultant magnetoresistive (MR) sensor element
structures have been disclosed in the art of magnetoresistive (MR)
sensor element fabrication for forming magnetically biased
magnetoresistive (MR) sensor elements with enhanced functionality,
enhanced reliability or other desirable properties.
For example, Voegeli et al., in U.S. Pat. No. 5,561,896, discloses
a method for fabricating, with enhanced longitudinal magnetic bias
characteristics, enhanced fabrication simplicity and enhanced
reliability, a longitudinally magnetically biased magnetoresistive
(MR) sensor element for use within magnetic data storage and
retrieval. The method employs an "H" shaped laminate formed of a
soft magnetoresistive (MR) material layer laminated to an
interdiffusion material layer, where upon thermally induced
interdiffusion of the soft magnetoresistive (MR) material layer and
the interdiffusion material layer there is formed a hard magnetic
bias material layer therefrom, and where interdiffusion of the soft
magnetoresistive (MR) material layer with the interdiffusion
material layer is effected by an electrical pulsing through a pair
of leg portions of the "H" but not a horizontal connector portion
of the "H", such that the pair of leg portions of the "H" is
transformed into a pair of hard magnetic bias material layers while
the horizontal connector portion of the "H" remains
un-interdiffused as the soft magnetoresistive (MR) material layer
which is longitudinally magnetically biased by the pair of hard
bias magnetic bias material layers formed from the thermally
interdiffused leg portions of the "H".
In addition, Dovek et al., in U.S. Pat. No. 5,650,887, discloses a
system for retrieving magnetic data from a magnetic data storage
medium while employing a spin valve magnetoresistive (SVMR) sensor
element, and a disk drive magnetic data storage enclosure which
employs the system for retrieving the magnetic data from the
magnetic data storage medium while employing the spin valve
magnetoresistive (SVMR) sensor element, where the spin-valve
magnetoresistive (SVMR) sensor element may be readily reset to its
original magnetic orientation subsequent to an event which
dislocates within the spin valve magnetoresistive (SVMR) sensor
element a magnetic exchange bias pinned layer from its original
magnetic orientation within the spin-valve magnetoresistive (SVMR)
sensor element. To achieve the foregoing result, the system
employs: (1) an electrical current waveform directed through the
spin-valve magnetoresistive (SVMR) sensor element with an initial
current sufficient to heat a magnetic exchange bias pinning layer
within the spin-valve magnetoresistive (SVMR) sensor element above
its blocking temperature; and (2) a subsequent lower current
sufficient to generate a magnetic field around the magnetic
exchange bias pinned layer pinned by the magnetic exchange bias
pinning layer to properly magnetically orient the magnetic exchange
bias pinned layer while the magnetic exchange bias pinning layer is
cooling below its blocking temperature.
Further, Shi et al., in U.S. Pat. No. 5,684,658, discloses a dual
stripe magnetoresistive (DSMR) sensor element and a method for
fabricating the dual stripe magnetoresistive (DSMR) sensor element,
where the dual stripe magnetoresistive (DSMR) sensor element has a
narrow read back width which in turn provides that the narrow read
back width dual stripe magnetoresistive (DSMR) sensor element may
be employed for reading digitally encoded magnetic data within
narrowly spaced tracks within a magnetic data storage medium. The
dual stripe magnetoresistive (DSMR) sensor element realizes the
foregoing object by employing when forming the dual stripe
magnetoresistive (DSMR) sensor element: (1) an offset of a first
magnetoresistive (MR) layer with respect to a second
magnetoresistive (MR) layer within the dual stripe magnetoresistive
(DSMR) sensor element; (2) a parallel longitudinal magnetic biasing
of the first magnetoresistive (MR) layer with respect to the second
magnetoresistive (MR) layer within the dual stripe magnetoresistive
(DSMR) sensor element; and (3) an anti-parallel electromagnetic
biasing of the first magnetoresistive (MR) layer with respect to
the second magnetoresistive (MR) layer within the dual stripe
magnetoresistive (DSMR) sensor element.
Still further, Han et al., in U.S. Pat. No. 5,783,460, discloses a
method for fabricating a dual stripe magnetoresistive (DSMR) sensor
element, where there is minimized tolerance variations with respect
to the width and/or alignment between a pair of magnetoresistive
(MR) layers within the dual stripe magnetoresistive (DSMR) sensor
element. To realize the foregoing object, the method employs a lift
off stencil as an etch mask for forming from a trilayer blanket
stack layer comprising: (1) a blanket first magnetoresistive (MR)
layer having formed thereupon; (2) a blanket inter-stripe
dielectric layer, in turn having formed thereupon; (3) a blanket
second magnetoresistive (MR) layer, a corresponding trilayer
patterned stack layer comprising: (1) patterned first
magnetoresistive (MR) layer having formed thereupon; (2) a
patterned inter-stripe dielectric layer in turn having formed
thereupon; (3) a patterned second magnetoresistive (MR) layer,
wherein the series of three foregoing patterned layers within the
trilayer patterned stack layer in turn has a series of fully
aligned edges.
Finally, Ohtsuka et al., in U.S. Pat. No. 5,859,753, discloses a
spin-valve magnetoresistive (SVMR) sensor element, and a method for
fabricating the spin-valve magnetoresistive (SVMR) sensor element,
where the spin-valve magnetoresistive (SVMR) sensor element has an
attenuated susceptibility to thermal asperities and electrostatic
discharge when employing the spin-valve magnetoresistive (SVMR)
sensor element for retrieving magnetic data from a magnetic data
storage medium. The spin-valve magnetoresistive (SVMR) sensor
element realizes the foregoing objects by employing a dual
spin-valve magnetoresistive (DSVMR) sensor element construction
wherein: (1) a pair of pinned magnetoresistive layers within the
dual spin-valve magnetoresistive (DSVMR) sensor element is
magnetically pinned in opposite directions; and (2) one conductor
lead layer within each pair of conductor lead layers employed
within the dual spin-valve magnetoresistive (DSVMR) sensor element
construction is positioned with respect to the magnetic data
storage medium from which is retrieved magnetic data further
removed than the other conductor lead layer within the pair of
conductor lead layers.
Desirable within the art of non-parallel magnetically biased
multiple magnetoresistive (MR) layer magnetoresistive (MR) sensor
element fabrication are additional methods and materials which may
be employed for forming non-parallel magnetically biased multiple
magnetoresistive (MR) layer magnetoresistive (MR) sensor elements
with enhanced magnetic bias profile uniformity of the non-parallel
magnetically biased multiple magnetoresistive (MR) layer
magnetoresistive (MR) sensor elements within the trackwidths of the
non-parallel magnetically biased multiple magnetoresistive (MR)
layer magnetoresistive (MR) sensor elements.
It is towards the foregoing object that the present invention is
directed.
SUMMARY OF THE INVENTION
A first object of the present invention is to provide a
non-parallel magnetically biased multiple magnetoresistive (MR)
layer magnetoresistive (MR) sensor element, and a method for
fabricating the non-parallel magnetically biased multiple
magnetoresistive (MR) layer magnetoresistive (MR) sensor element,
where the non-parallel magnetically biased multiple
magnetoresistive (MR) layer magnetoresistive (MR) sensor element
has an enhanced magnetic bias profile uniformity within a
trackwidth of the non-parallel magnetically biased multiple
magnetoresistive (MR) layer magnetoresistive (MR) sensor
element.
A second object of the present invention is to provide a
non-parallel magnetically biased multiple magnetoresistive (MR)
layer magnetoresistive (MR) sensor element and a method for
fabricating the non-parallel magnetically biased multiple
magnetoresistive (MR) layer magnetoresistive (MR) sensor element in
accord with the first object of the present invention, which method
is readily commercially implemented.
In accord with the objects of the present invention, there is
provided by the present invention a method for fabricating a
non-parallel magnetically biased multiple magnetoresistive (MR)
layer magnetoresistive (MR) sensor element. To practice the method
of the present invention, there is first provided a substrate.
There is then formed over the substrate a first magnetoresistive
(NM) layer. There is also formed contacting the first
magnetoresistive (MR) layer a magnetically biased first magnetic
bias layer, where the magnetically biased first magnetic bias layer
is biased in a first magnetic bias direction with a first magnetic
bias field strength. There is also formed separated from the first
magnetoresistive (MR) layer by a spacer layer a second
magnetoresistive (MR) layer. There is also formed contacting the
second magnetoresistive (MR) layer a magnetically un-biased second
magnetic bias layer. There is then biased through use of a first
thermal annealing method employing a first thermal annealing
temperature, a first thermal annealing exposure time and a first
extrinsic magnetic bias field strength the magnetically un-biased
second magnetic bias layer to form a magnetically biased second
magnetic bias layer having a second magnetic bias field strength in
a second magnetic bias direction non-parallel to the first magnetic
bias direction while simultaneously partially demagnetizing the
magnetically biased first magnetic bias layer to form a partially
demagnetized magnetically biased first magnetic bias layer having a
partially demagnetized first magnetic bias field strength less than
the first magnetic bias field strength. Finally, there is then
annealed thermally through use of a second thermal annealing
employing a second thermal annealing temperature and a second
thermal annealing exposure time without a second magnetic bias
field: (1) the partially demagnetized magnetically biased first
magnetic bias layer to form a remagnetized partially demagnetized
first magnetic bias layer having a remagnetized partially
demagnetized first magnetic bias field strength greater than the
partially demagnetized first magnetic bias field strength; and (2)
the magnetically biased second magnetic bias layer to form a
further magnetically biased second magnetic bias layer having a
further magnetized second magnetic bias field strength greater than
the second magnetic bias field strength.
Advantageously, the method of the present invention provides that:
(1) a first magnetic bias layer from which is formed the
magnetically biased first magnetic bias layer; and (2) the second
magnetic bias layer, may both be formed from a single magnetic bias
material. Thus, use of such a single magnetic bias material assists
in optimizing a cross-track magnetic bias profile uniformity of a
non-parallel magnetically biased multiple magnetoresistive (MR)
layer magnetoresistive (MR) sensor element. To the extent not
previously disclosed or claimed within the art of magnetoresistive
(MR) sensor element fabrication, the present invention also
contemplates various non-parallel magnetically biased multiple
magnetoresistive (MR) layer magnetoresistive (MR) sensor elements
formed employing multiple non-parallel magnetically biased magnetic
bias layers formed of a single magnetic bias material.
The present invention provides a non-parallel magnetically biased
multiple magnetoresistive (MR) layer magnetoresistive (MR) sensor
element, and a method for fabricating the non-parallel magnetically
biased multiple magnetoresistive (MR) layer magnetoresistive (MR)
sensor element, where the non-parallel magnetically biased multiple
magnetoresistive (MR) layer magnetoresistive (MR) sensor element
has an enhanced magnetic bias profile uniformity within a
trackwidth of the non-parallel magnetically biased multiple
magnetoresistive (MR) layer magnetoresistive (MR) sensor element.
The method of the present invention realizes the foregoing object
by employing when fabricating the non-parallel magnetically biased
multiple magnetoresistive (MR) layer magnetoresistive (MR) sensor
element: (1) a first thermal annealing method employing a first
thermal annealing temperature, a first thermal annealing exposure
time and a first extrinsic magnetic bias field strength to form
from a magnetically un-biased second magnetic bias layer a
magnetically biased second magnetic bias layer having a second
magnetic bias field strength in a second magnetic bias direction
non-parallel to a first magnetic bias direction of a magnetically
biased first magnetic bias layer, while simultaneously partially
demagnetizing the magnetically biased first magnetic bias layer to
provide a partially demagnetized magnetically biased first magnetic
bias layer having a partially demagnetized first magnetic bias
field strength less than a first magnetic bias field strength; and
(2) a second thermal annealing method employing a second thermal
annealing temperature and a second thermal annealing exposure time
without a second magnetic bias field: (a) to form from the
partially demagnetized magnetically biased first magnetic bias
layer a remagnetized partially demagnetized first magnetic bias
layer having a remagnetized partially demagnetized first magnetic
bias field strength greater than the partially demagnetized first
magnetic bias field strength; and (b) to form from the magnetically
biased second magnetic bias layer a further magnetically biased
second magnetic bias layer having a further magnetized second
magnetic bias field strength greater than the second magnetic bias
field strength.
The method of the present invention is readily commercially
implemented. The method of the present invention employs thermal
annealing methods which are generally known in the art of
magnetoresistive (MR) sensor element fabrication. Since it is a
process control within the present invention which provides at
least in part the method of the present invention, rather than the
existence of methods and materials which provides the present
invention, the method of the present invention is readily
commercially implemented.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects, features and advantages of the present invention are
understood within the context of the Description of the Preferred
Embodiment, as set forth below. The Description of the Preferred
Embodiment is understood within the context of the accompanying
drawings, which form a material part of this disclosure,
wherein:
FIG. 1, FIG. 2, FIG. 3a, FIG. 3b, FIG. 4a, FIG. 4b, FIG. 5a, FIG.
5b and FIG. 6 show a series of schematic air bearing surface (ABS)
view diagrams and schematic perspective view diagrams illustrating
the results of progressive stages in forming a merged inductive
magnetic write dual stripe magnetoresistive (DSMR) read magnetic
read-write head having formed therein an anti-parallel magnetically
biased dual stripe magnetoresistive (DSMR) sensor element in accord
with a preferred embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention provides a non-parallel magnetically biased
multiple magnetoresistive (MR) layer magnetoresistive (MR) sensor
element, and a method for fabricating the non-parallel magnetically
biased multiple magnetoresistive (MR) layer magnetoresistive (MR)
sensor element, where the non-parallel magnetically biased multiple
magnetoresistive (MR) layer magnetoresistive (MR) sensor element
has an enhanced magnetic bias profile uniformity within a
trackwidth of the non-parallel magnetically biased multiple
magnetoresistive (MR) layer magnetoresistive (MR) sensor element.
The method of the present invention realizes the foregoing objects
by employing when forming the non-parallel magnetically biased
multiple magnetoresistive (MR) layer magnetoresistive (MR) sensor
element: (1) a first thermal annealing method employing a first
thermal annealing temperature, a first thermal annealing exposure
time and a first extrinsic magnetic bias field strength to form
from a magnetically un-biased second magnetic bias layer a
magnetically biased second magnetic bias layer having a second
magnetic bias field strength in a second magnetic bias direction
non-parallel to a first magnetic bias direction of a magnetically
biased first magnetic bias layer while simultaneously partially
demagnetizing the magnetically biased first magnetic bias layer to
provide a partially demagnetized magnetically biased first magnetic
bias layer having a partially demagnetized first magnetic bias
field strength less than the first magnetic bias field strength;
and (2) a second thermal annealing method employing a second
thermal annealing temperature and a second thermal annealing
exposure time without a second magnetic bias field: (a) to form
from the partially demagnetized magnetically biased first magnetic
bias layer a remagnetized partially demagnetized first magnetic
bias layer having a remagnetized partially demagnetized first
magnetic bias field strength greater than the partially
demagnetized first magnetic bias field strength; and (b) to form
from the magnetically biased second magnetic bias layer a further
magnetically biased second magnetic bias layer having a further
magnetized second magnetic bias field strength greater than the
second magnetic bias field strength.
Although the preferred embodiment of the present invention
illustrates the present invention within the context of fabricating
within a merged inductive magnetic write dual stripe
magnetoresistive (DSMR) read magnetic read-write head which is most
likely to be employed within digitally encoded magnetic data
storage and retrieval an anti-parallel magnetically biased dual
stripe magnetoresistive (DSMR) sensor element, the method of the
present invention may be employed in forming non-parallel
magnetically biased multiple magnetoresistive (MR) layer
magnetoresistive (MR) sensor elements other than only anti-parallel
magnetically biased dual stripe magnetoresistive (DSMR) sensor
elements. Such other non-parallel magnetically biased multiple
magnetoresistive (MR) layer magnetoresistive (MR) sensor elements
may include, but are not limited to, non-parallel magnetically
biased dual stripe magnetoresistive (DSMR) sensor elements other
than anti-parallel magnetically biased dual stripe magnetoresistive
(DSMR) sensor elements and non-parallel magnetically biased
multiple magnetoresistive (MR) layer magnetoresistive layer
magnetoresistive (MR) sensor elements other than dual stripe
magnetoresistive (DSMR) sensor elements. The latter category may
include, but is not limited to a dual spin valve magnetoresistive
(DSVMR) sensor element as is disclosed, for example and without
limitation within Ohtsuka et al, within U.S. Pat. No. 5,859,753, as
cited within the Description of the Related Art, the teachings of
all of which related art are incorporated herein fully by
reference.
Similarly, in a more fundamental sense, the present invention
provides a method for at least partially remagnetizing a partially
demagnetized magnetic bias layer which may be employed within a
magnetoresistive (MR) sensor element, typically under circumstances
where the partially demagnetized magnetic bias layer has been
partially demagnetized incident to magnetically biasing an
additional magnetic bias layer within the magnetoresistive (MR)
sensor element or incident to some other demagnetizing incident
experienced by the magnetoresistive (MR) sensor element. The
magnetoresistive (MR) sensor element wherein the partially
demagnetized magnetic bias layer may be remagnetized may be
selected from the group including but not limited to single stripe
magnetoresistive (SSMR) sensor elements, dual stripe
magnetoresistive (DSMR) sensor elements, spin valve
magnetoresistive (SVMR) sensor elements and dual spin valve
magnetoresistive (DSVMR) sensor elements. See, e.g., Dovek et al.,
U.S. Pat. No. 5,650,887, as cited within the Description of the
Related Art.
Finally, a non-parallel magnetically biased multiple
magnetoresistive (MR) layer magnetoresistive (MR) sensor element
fabricated in accord with the present invention may be employed
within a magnetic sensor within magnetic sensor applications
including but not limited to digital magnetic sensor applications
and analog magnetic sensor applications employing magnetic heads
including but not limited to merged inductive magnetic write
magnetoresistive (MR) read magnetic read-write heads, non-merged
inductive magnetic write magnetoresistive (MR) read magnetic
read-write heads, and read only magnetoresistive (MR) read
heads.
Referring now to FIG. 1 to FIG. 6, there is shown a series of
schematic air bearing surface (ABS) view diagrams and schematic
perspective view diagrams illustrating the results of progressive
stages in fabrication of a merged inductive magnetic write dual
stripe magnetoresistive (DSMR) read magnetoresistive (MR) sensor
element having fabricated therein a nominally anti-parallel
non-parallel longitudinally magnetically biased dual stripe
magnetoresistive (DSMR) sensor element in accord a preferred
embodiment of the present invention. Shown in FIG. 1 is a schematic
air bearing surface (ABS) view diagram of the merged inductive
magnetic write dual stripe magnetoresistive (DSMR) read
magnetoresistive (MR) sensor element at an early stage in its
fabrication in accord with the preferred embodiment of the present
invention.
Shown in FIG. 1 is a substrate 10 having formed thereupon a blanket
first shield layer 12 which in turn has formed thereupon a blanket
first non-magnetic spacer layer 14. Within the preferred embodiment
of the present invention with respect to the substrate 10, the
blanket first shield layer 12 and the blanket first non-magnetic
spacer layer 14, the substrate 10, the blanket first shield layer
12 and the blanket first non-magnetic spacer layer 14 may be formed
employing methods and materials as are conventional in the art of
magnetoresistive (MR) sensor element fabrication.
For example, although it is known in the art of magnetoresistive
(MR) sensor element fabrication that substrates are typically
formed from non-magnetic ceramic materials such as but not limited
to oxides, nitrides, borides and carbides, as well as homogeneous
and heterogeneous mixtures of oxides, nitrides, borides and
carbides, for the preferred embodiment of the present invention,
the substrate 10 is typically and preferably formed from a
non-magnetic aluminum oxide/titanium carbide ceramic material.
Preferably, the substrate 10 is formed with sufficient dimensions
to allow the substrate 10 to be fabricated into a slider employed
within a magnetic head employed within a direct access storage
device (DASD) magnetic data storage enclosure employed within
digitally encoded magnetic data storage and retrieval, although, as
noted above, a magnetoresistive (MR) sensor element fabricated in
accord with the present invention may be employed within other
digital magnetic storage and transduction applications, as well as
analog magnetic signal storage and transduction applications.
Similarly, although it is also known in the art of magnetoresistive
(MR) sensor element fabrication that shield layers may be formed
from any of several soft magnetic materials, including but not
limited to nickel-iron permalloy alloy soft magnetic materials and
higher order alloy soft magnetic materials incorporating
nickel-iron permalloy alloy soft magnetic materials (ie:
nickel-iron-rhodium soft magnetic materials and
nickel-iron-chromium soft magnetic materials), for the preferred
embodiment of the present invention, the blanket first shield layer
12 is preferably formed of a nickel-iron (80:20 w/w) permalloy
alloy soft magnetic material. Typically and preferably, the blanket
first shield layer 12 is formed to a thickness of from about 10000
to about 30000 angstroms.
Finally, within the preferred embodiment of the present invention
with respect to the blanket first non-magnetic spacer layer 14,
although the blanket first non-magnetic spacer layer 14 may be
formed employing methods and materials as are conventional in the
art of magnetoresistive (MR) sensor element fabrication, including
but not limited to chemical vapor deposition (CVD) methods, plasma
enhanced chemical vapor deposition (PECVD) methods and physical
vapor deposition (PVD) sputtering methods through which may be
formed non-magnetic spacer layers of non-magnetic spacer materials
including but not limited to conductor non-magnetic spacer
materials and dielectric non-magnetic spacer materials (such
dielectric non-magnetic spacer materials including but not limited
to silicon oxide dielectric materials, silicon nitride dielectric
materials, nitrogenated carbon dielectric materials and aluminum
oxide dielectric materials), for the preferred embodiment of the
present invention, the blanket first non-magnetic spacer layer 14
is preferably formed of an aluminum oxide non-magnetic dielectric
spacer material deposited employing a physical vapor deposition
(PVD) sputtering method, as is most common in the art of
magnetoresistive (MR) sensor element fabrication. Preferably, the
blanket first non-magnetic spacer layer 14 so formed is formed to a
thickness of from about 100 to about 500 angstroms.
Although not completely illustrated within the schematic
air-bearing surface (ABS) view diagram of FIG. 1, there is also
shown within FIG. 1 formed upon the blanket first non-magnetic
spacer layer 14 a patterned first magnetoresistive (MR) layer 16.
Typically and preferably, the patterned first magnetoresistive (MR)
layer 16 is formed from a magnetoresistive (MR) material analogous
or equivalent to the soft magnetic material employed for forming
the blanket first shield layer 12. Preferably, the patterned first
magnetoresistive (MR) layer 16 is formed upon the blanket first
non-magnetic spacer layer 14 from a nickel-iron (80:20; w/w)
permalloy alloy magnetoresistive material to a thickness of from
about 50 to about 200 angstroms, a length (i.e. long axis or "easy"
axis) of from about 0.3 to about 5 microns and a width (i.e. short
axis of "hard" axis) of from about 0.3 to about 1.0 microns.
Finally, there is also shown within the schematic air-bearing
surface (ABS) view diagram of FIG. 1 a pair of magnetically
un-biased patterned first longitudinal magnetic bias layers 18a and
18b formed upon a pair of opposite ends of the long axis of the
patterned first magnetoresistive (MR) layer 16 to define a first
trackwidth TW1 of the patterned first magnetoresistive (MR) layer
16. Preferably, the first trackwidth TW1 is from about 0.1 to about
3 microns. The pair of magnetically un-biased patterned first
longitudinal magnetic bias layers 18a and 18b may be formed of
longitudinal magnetic bias materials as are known in the art of
magnetoresistive (MR) sensor element fabrication, including but not
limited to: (1) antiferromagnetic longitudinal magnetic bias
materials (such as but not limited to iron-manganese alloy
longitudinal magnetic biasing materials, nickel-manganese
longitudinal magnetic biasing materials, iridium-manganese alloy
longitudinal magnetic biasing materials, platinum-manganese alloy
longitudinal magnetic biasing materials,
platinum-palladium-manganese alloy longitudinal magnetic biasing
materials and additional related and higher order alloys thereof),
as well as; (2) permanent magnet longitudinal magnetic bias
materials (such as but not limited to platinum-cobalt alloy
longitudinal magnetic biasing materials, higher order alloys
incorporating platinum-cobalt alloy longitudinal magnetic biasing
materials, cobalt-chromium alloy longitudinal magnetic biasing
materials and rare earth alloy longitudinal magnetic biasing
materials). Preferably, each of the magnetically un-biased
patterned first longitudinal magnetic bias layers 18a and 18b is
formed of an antiferromagnetic longitudinal magnetic bias material,
preferably a nickel-manganese alloy (50:50, w/w) antiferromagnetic
longitudinal magnetic bias material, preferably to a thickness of
from about 100 to about 300 angstroms each.
Although not illustrated within the schematic air bearing surface
(ABS) view diagram of FIG. 1, there is typically and preferably
also formed coextensively upon the pair of magnetically un-biased
patterned first longitudinal magnetic bias layers 18a and 18b a
pair of patterned first conductor lead layers. Illustration of the
pair of patterned first conductor lead layers is omitted from the
schematic air bearing surface (ABS) view diagram of FIG. 1, in
order to provide clarity. Typically and preferably, the pair of
patterned first conductor lead layers may be formed simultaneously
with the pair of magnetically un-biased patterned first
longitudinal magnetic bias layers 18a and 18b while employing a
lift-off method. Typically and preferably, each patterned first
conductor lead layer within the pair of patterned first conductor
lead layers is formed to a thickness of from about 500 to about
1000 angstroms while employing a conductor lead material
conventional in the art of magnetoresistive (MR) sensor element
fabrication, such a conductor lead material being selected from the
group of conductor lead materials including but not limited to
aluminum, aluminum alloy, copper, copper alloy, tungsten, tungsten
alloy, tantalum, tantalum alloy, gold and gold alloy conductor lead
materials, as well as laminates thereof
Finally, although the schematic air-bearing surface (ABS) view
diagram of FIG. 1 illustrates the pair of magnetically unbiased
patterned first longitudinal magnetic bias layers 18a and 18b
formed upon the patterned first magnetoresistive layer 16, it is
also feasible within the present invention that a pair of
magnetically un-biased or magnetically biased patterned first
longitudinal magnetic biasing layers, analogous to the pair of
magnetically unbiased patterned first longitudinal magnetic bias
layers 18a and 18b, either abuts or is formed beneath a patterned
first magnetoresistive (MR) layer, such as the patterned first
magnetoresistive (MR) layer 16, provided that the pair of
magnetically un-biased or magnetically biased patterned first
longitudinal magnetic bias layers contacts a pair of opposite ends
of the patterned first magnetoresistive (NM) layer to define a
first trackwidth of the patterned first magnetoresistive (MR)
layer.
Referring now to FIG. 2, there is shown a schematic air bearing
surface (ABS) view diagram illustrating the results of further
processing of the merged inductive magnetic write dual stripe
magnetoresistive (DSMR) read magnetoresistive (MR) sensor element
whose schematic air bearing surface (ABS) view diagram is
illustrated in FIG. 1. Shown in FIG. 2 is a schematic air bearing
surface (ABS) view diagram of a merged inductive magnetic write
dual stripe magnetoresistive (DSMR) read magnetoresistive (MR)
sensor element otherwise equivalent to the inductive magnetic write
dual stripe magnetoresistive (DSMR) read magnetoresistive (MR)
sensor element whose schematic cross-sectional diagram is
illustrated in FIG. 1, but wherein the magnetically un-biased
patterned first longitudinal magnetic bias layers 18a and 18b are
longitudinally magnetically biased by thermal annealing within a
first thermal annealing method under the influence of a first
extrinsic magnetic bias field HI to longitudinally magnetically
bias the pair of magnetically un-biased patterned first
longitudinal magnetic bias layers 18a and 18b in a direction
substantially parallel with an axis which separates the pair of
magnetically un-biased patterned first longitudinal magnetic bias
layers 18a and 18b, thus forming from the pair of magnetically
un-biased patterned first longitudinal magnetic bias layers 18a and
18b a pair of magnetically biased patterned first longitudinal
magnetic biasing layers 18a' and 18b'.
Although the preferred embodiment of the present invention
illustrates the longitudinal magnetic biasing of the pair of
magnetically un-biased patterned first longitudinal magnetic bias
layers 18a and 18b to form the pair of magnetically biased
patterned first longitudinal magnetic bias layers 18a' and 18b' by
employing the first extrinsic magnetic bias field H1 while
employing the first thermal annealing method after forming the pair
of magnetically un-biased patterned first longitudinal magnetic
bias layers 18a and 18b, it is also feasible within the method of
the present invention that the magnetically biased patterned first
longitudinal magnetic bias layers 18a' and 18b' may be formed
directly incident to forming the otherwise magnetically un-biased
patterned first longitudinal magnetic biasing layers 18a and 18b
within the first extrinsic magnetic bias field H1 when originally
forming the pair of otherwise magnetically un-biased patterned
first longitudinal magnetic bias layers 18a and 18b.
Within the preferred embodiment of the present invention, the
magnetically biased patterned first longitudinal magnetic bias
layers 18a' and 18b' are preferably formed employing the first
thermal annealing method wherein the inductive magnetic write dual
stripe magnetoresistive (DSMR) read magnetoresistive (MR) sensor
element whose schematic air bearing surface (ABS) view diagram is
illustrated in FIG. 1 is thermally annealed within the first
extrinsic magnetic bias field H1 of strength from about 500 to
about 2000 oersteds for a time period of from about 5 to about 10
hours and a temperature of about 280 to about 300 degrees
centigrade, under circumstances where the magnetically un-biased
patterned first longitudinal magnetic bias layers 18a and 18b are
each formed of a nickel-manganese (50:50; w/w) antiferromagnetic
longitudinal magnetic bias material as is conventional in the art
of magnetoresistive (MR) sensor element fabrication. Under such
first thermal annealing conditions, it is expected that the pair of
magnetically biased patterned first longitudinal magnetic bias
layers 18a' and 18b' is fully magnetically saturated in a first
magnetic bias direction with a first magnetic bias field strength.
More preferably, and although not specifically illustrated within
the schematic cross-sectional diagram of FIG. 2, the magnetically
biased patterned first longitudinal magnetic bias layers 18a' and
18b' are preferably formed employing the first thermal annealing
method wherein the merged inductive write dual stripe
magnetoresistive (DSMR) read magnetoresistive (MR) sensor element
whose schematic cross-sectional diagram is illustrated in FIG. 1,
but over which is formed a patterned second magnetoresistive (MR)
layer, is thermally annealed while employing the first thermal
annealing method employing the first extrinsic magnetic bias field
H1 employing the above recited thermal annealing conditions. Under
such circumstances, the patterned first magnetoresistive (MR) layer
16 and the patterned second magnetoresistive (MR) layer will
typically, incident to their simultaneous thermal annealing, have
correlating resistance and magnetoresistance (MR) properties.
Although the schematic air-bearing surface (ABS) view diagram of
FIG. 2 implicitly illustrates the magnetically biased patterned
first longitudinal magnetic biasing layers 18a' and 18b' as
nominally completely aligned with a major axis which separates the
pair of magnetically biased patterned first longitudinal magnetic
bias layers 18a' and 18b', it is understood by a person skilled in
the art that the magnetically biased patterned first longitudinal
magnetic bias layers 18a' and 18b' will typically and preferably be
only substantially aligned with an acute divergent angle of up to
about 60 degrees, and more preferably from about 30 to about 50
degrees, from the major axis of complete alignment. Such
substantial alignment is typical incident to thermal annealing
methods and magnetically assisted deposition methods as are
conventional in the art of magnetoresistive (MR) sensor element
fabrication, and such substantial alignment, rather than complete
alignment, provides optimal magnetoresistive (MR) properties to a
dual stripe magnetoresistive (DSMR) sensor element.
Referring now to FIG. 3a, there is shown a schematic air bearing
surface (ABS) view diagram illustrating the results of further
processing of the merged inductive magnetic write dual stripe
magnetoresistive (DSMR) read magnetoresistive (MR) sensor element
whose schematic air bearing surface (ABS) view diagram is
illustrated in FIG. 2. Shown in FIG. 3a is a schematic air bearing
surface (ABS) view diagram of a merged inductive magnetic write
dual stripe magnetoresistive (DSMR) read magnetoresistive (MR)
sensor element otherwise equivalent to the merged inductive
magnetic write dual stripe magnetoresistive (MR) read
magnetoresistive (MR) sensor element whose schematic air bearing
surface (ABS) view diagram is illustrated in FIG. 2 but wherein:
(1) there is formed upon the pair of magnetically biased patterned
first longitudinal magnetic biasing layers 18a' and 18b' and upon
the first trackwidth TW1 of the patterned first magnetoresistive
(MR) layer 16 a blanket second non-magnetic spacer layer 20; (2)
there is formed upon the blanket second non-magnetic spacer layer
20 a patterned second magnetoresistive layer 22; and (3) there is
formed upon the patterned second magnetoresistive (MR) layer 22 a
pair of magnetically un-biased patterned second longitudinal
magnetic bias layers 24a and 24b which define a second trackwidth
TW2 of the patterned second magnetoresistive (MR) layer 22.
Preferably, the second trackwidth TW2 is of a width and alignment
corresponding with the first trackwidth TW1. It is further noted
that the patterned first magnetoresistive (MR) layer 16 and the
patterned second magnetoresistive (MR) layer 22 may each also be a
magnetoresistive sensor structure such as a spin-valve
magnetoresistive (SVMR) sensor structure which is well known in the
art and is described in detail within the prior art of Dovek et al.
and Ohtsuka et al. (cited above), both of which are fully
incorporated herein by reference. If layers 16 and 22 are SVMR
structures, the sensor so endowed will be a dual spin-valve
magnetoresistive (DSMVR) sensor rather than a dual stripe
magnetoresistive (DSMR) sensor.
Within the preferred embodiment of the present invention, the
blanket second non-magnetic spacer layer 20 is preferably formed
employing methods and materials analogous or equivalent to the
methods and materials preferably employed for forming the blanket
first non-magnetic spacer layer 14. Typically and preferably, the
blanket second non-magnetic spacer layer 20 is formed of an
aluminum oxide non-magnetic dielectric spacer material formed to a
thickness of from about 200 to about 500 angstroms. Similarly,
within the preferred embodiment of the present invention, the
patterned second magnetoresistive layer 22 is preferably formed
employing methods, materials and dimensions analogous or equivalent
to the methods, materials and dimensions employed for forming the
patterned first magnetoresistive layer 16. Finally, within the
preferred embodiment of the present invention, the pair of
magnetically un-biased patterned second longitudinal magnetic bias
layers 24a and 24b is preferably formed employing methods,
materials and dimensions analogous or equivalent to the methods,
materials and dimensions employed for forming the pair of
magnetically un-biased patterned first longitudinal magnetic bias
layers 18a and 18b. In particular, the pair of magnetically
un-biased patterned second longitudinal magnetic bias layers 24a
and 24b and the pair of magnetically un-biased patterned first
longitudinal magnetic bias layers 18a and 18b are preferably but
not necessarily formed of a single longitudinal magnetic biasing
material. Analogously with the magnetically un-biased patterned
first longitudinal magnetic biasing layers 18a and 18b, and
similarly also not illustrated within the schematic air bearing
surface (ABS) view diagram of FIG. 3a, the pair of magnetically
un-biased patterned second longitudinal magnetic bias layers 24a
and 24b also preferably has formed and aligned thereupon, while
similarly also preferably employing a lift off method, a pair of
patterned second conductor lead layers formed employing materials
and dimensions analogous or equivalent to the materials and
dimensions employed for forming the pair of patterned first
conductor lead layers.
Referring now to FIG. 3b, there is shown a schematic perspective
view diagram corresponding with the schematic cross-sectional
diagram of FIG. 3a. Shown in FIG. 3b is the patterned first
magnetoresistive (MR) layer 16 having formed upon a pair of its
opposite ends the pair of magnetically biased patterned first
longitudinal magnetic bias layers 18a' and 18b' which are
preferably formed fully saturated in a first magnetic bias
direction with a first magnetic bias field strength. Similarly,
there is also shown within FIG. 3b the patterned second
magnetoresistive (MR) layer 22 having formed and aligned thereupon
the pair of magnetically un-biased patterned second longitudinal
magnetic bias layers 24a and 24b. All other layers within the
merged inductive magnetic write dual stripe magnetoresistive (DSMR)
read magnetoresistive (MR) sensor element whose schematic air
bearing surface (ABS) view diagram is illustrated in FIG. 3a have
been omitted for clarity.
Referring now to FIG. 4a, there is shown a schematic air bearing
surface (ABS) view diagram illustrating the results of further
processing of the merged inductive magnetic write dual stripe
magnetoresistive (DSMR) read magnetoresistive (MR) sensor element
whose schematic air bearing surface (ABS) view diagram is
illustrated in FIG. 3a. Shown in FIG. 4a is a schematic air bearing
surface (ABS) view diagram of a merged inductive magnetic write
dual stripe magnetoresistive (DSMR) read magnetoresistive (MR)
sensor element otherwise equivalent to the merged inductive
magnetic write dual stripe magnetoresistive (DSMR) read
magnetoresistive (MR) sensor element whose schematic air bearing
surface (ABS) view diagram is illustrated in FIG. 3a, but wherein
the magnetically un-biased patterned second longitudinal magnetic
biasing layers 24a and 24b have been longitudinally magnetically
biased while employing a second thermal annealing method employing
a second extrinsic magnetic bias field H2 nominally anti-parallel
to the first extrinsic magnetic bias field H1 as illustrated within
the schematic air bearing surface (ABS) view diagram of FIG. 2, to
provide the magnetically biased patterned second longitudinal
magnetic bias layers 24a' and 24b'.
Within the preferred embodiment of the present invention, the
magnetically un-biased patterned second longitudinal magnetic bias
layers 24a and 24b are longitudinally magnetically biased
substantially nominally anti-parallel with respect to the
magnetically biased patterned first longitudinal magnetic biasing
layers 18a' and 18b' as illustrated in FIG. 2, while employing the
second thermal annealing method which employs a second thermal
annealing temperature and a second thermal annealing exposure time,
in conjunction with the second extrinsic magnetic bias field H2 of
appropriate magnetic field strength, such that the pair of
magnetically un-biased patterned second longitudinal magnetic
biasing layers 24a and 24b is longitudinally magnetically biased to
form the pair of magnetically biased patterned second longitudinal
magnetic bias layers 24a' and 24b' while substantially but not
completely de-magnetizing the pair of magnetically biased patterned
first longitudinal magnetic bias layers 18a' and 18b' which then
form a pair of partially demagnetized magnetically biased patterned
first longitudinal magnetic bias layers 18a" and 18b", as
illustrated within the schematic air bearing surface (ABS) view
diagram of FIG. 4a.
For the preferred embodiment of the present invention when both the
pair of magnetically biased patterned first longitudinal magnetic
bias layers 18a' and 18b', as well as the pair of magnetically
un-biased patterned second longitudinal magnetic bias layers 24a
and 24b, are formed of a nickel-manganese alloy (50:50, w/w)
antiferromagnetic longitudinal magnetic bias material, the pair of
magnetically un-biased patterned second longitudinal magnetic
biasing layers 24a and 24b is preferably thermally annealed at the
second thermal annealing temperature of from about 250 to about 275
degrees centigrade for a second thermal annealing exposure time
period of from about 0.5 to about 1.5 hours within the second
extrinsic magnetic bias field H2 of strength about 1000 to about
2000 oersteds. Preferably, each of the first thermal annealing
method and the second thermal annealing method also employs a
nitrogen atmosphere.
Within the present invention, it is preferred that the pair of
magnetically biased patterned first longitudinal magnetic bias
layers 18a' and 18b' be substantially demagnetized when forming the
pair of partially demagnetized patterned first longitudinal
magnetic bias layers 18a" and 18b" to provide the pair of partially
demagnetized patterned first longitudinal magnetic bias layers with
a partially demagnetized first magnetic bias field strength of no
less than about 25 to about 30 percent (more preferably from about
30 to about 50 percent) of the first magnetic bias field strength,
while still maintaining the first magnetic bias field direction,
when forming the pair of partially demagnetized magnetically biased
patterned first longitudinal magnetic bias layers 18a" and 18b"
incident to forming the pair of magnetically biased patterned
second longitudinal magnetic bias layers 24a' and 24b' from the
pair of magnetically unbiased patterned second longitudinal
magnetic bias layers 24a and 24b. Thus, within the present
invention, there is balanced at an appropriate second thermal
annealing temperature, second thermal annealing exposure time and
second extrinsic magnetic bias field H2 strength a magnetization of
the pair of magnetically un-biased patterned second longitudinal
magnetic bias layers 24a and 24b in comparison with a
demagnetization of the pair of magnetically biased patterned first
longitudinal magnetic bias layers 18a' and 18b'.
Similarly, although not specifically illustrated within the
preferred embodiment of the present invention, within the present
invention, generally, the extrinsic first magnetic bias field H1
and the extrinsic second magnetic bias field H2 need only be
non-parallel, rather than anti-parallel.
Referring now to FIG. 4b, there is shown a schematic perspective
view diagram corresponding with the schematic cross-sectional
diagram of FIG. 4a. Shown in FIG. 4b is the patterned first
magnetoresistive (MR) layer 16 having formed upon a pair of its
opposite ends the pair of partially demagnetized magnetically
biased patterned first longitudinal magnetic bias layers 18a" and
18b". Similarly, there is also shown within FIG. 4b the patterned
second magnetoresistive layer 22 having formed and aligned upon a
pair of its opposite ends the pair of magnetically biased patterned
second longitudinal magnetic bias layers 24a' and 24b'. As is
illustrated within the schematic perspective view diagram of FIG.
4b, the pair of magnetically biased patterned second longitudinal
magnetic biasing layers 24a' and 24b' is partially magnetized while
the pair of partially demagnetized magnetically biased patterned
first longitudinal magnetic bias layers 18a" and 18b" is not
completely demagnetized. All other layers within the merged
inductive magnetic write dual stripe magnetoresistive (DSMR) read
magnetoresistive (MR) sensor element whose schematic air bearing
surface (ABS) view diagram is illustrated in FIG. 4a have been
omitted for clarity.
Similarly, although both FIG. 4a and FIG. 4b illustrate the results
of the second thermal annealing method for forming the pair of
magnetically biased patterned second longitudinal magnetic biasing
layers 24a' and 24b' as occurring immediately after forming the
pair of magnetically unbiased patterned second longitudinal
magnetic biasing layers 24a and 24b upon the patterned second
magnetoresistive (MR) layer 22, within the method of the present
invention, the second thermal annealing may often preferably be
undertaken at a later stage in processing of the merged inductive
magnetic write dual stripe magnetoresistive (DSMR) read
magnetoresistive (MR) sensor element whose schematic air bearing
surface (ABS) view diagram is illustrated in FIG. 4a and whose
schematic perspective view diagram is illustrated in FIG. 4b. For
example, and without limitation, the second thermal annealing may
be undertaken after write element structures are formed within the
merged inductive magnetic write dual stripe magnetoresistive (DSMR)
read magnetoresistive (MR) sensor element whose schematic air
bearing surface (ABS) view diagram is illustrated in FIG. 4a and
whose schematic perspective view diagram is illustrated in FIG. 4b.
Under such circumstances, the second thermal annealing may, for
example, thermally anneal and stabilize a magnetic write pole layer
and a magnetic write coil layer.
Referring now to FIG. 5a, there is shown a schematic air bearing
surface (ABS) view diagram illustrating the results of further
processing of the merged inductive magnetic write dual stripe
magnetoresistive (DSMR) read magnetoresistive (MR) sensor element
whose schematic air bearing surface (ABS) view diagram is
illustrated in FIG. 4a.
Shown in FIG. 5a is a schematic air bearing surface (ABS) view
diagram of a merged inductive magnetic write dual stripe
magnetoresistive (DSMR) read magnetoresistive (MR) sensor element
otherwise equivalent to the merged inductive magnetic write dual
stripe magnetoresistive (DSMR) read magnetoresistive (MR) sensor
element whose schematic air bearing surface (ABS) view diagram is
illustrated in FIG. 4a, but wherein the merged inductive magnetic
write dual stripe magnetoresistive (DSMR) read magnetoresistive
(MR) sensor element has been thermally annealed while employing a
third thermal annealing method employing a third thermal annealing
temperature and a third thermal annealing exposure time without a
third extrinsic magnetic bias field to: (1) form from the partially
demagnetized magnetically biased patterned first longitudinal
magnetic bias layers 18a" and 18b" a corresponding pair of
remagnetized partially demagnetized magnetically biased patterned
first longitudinal magnetic bias layers 18'" and 18b'" having a
remagnetized partially demagnetized first magnetic bias field
strength in the first magnetic bias direction and greater than the
partially demagnetized first magnetic bias field strength; and (2)
form from the pair of magnetically biased patterned second
longitudinal magnetic bias layers 24a' and 24b' a pair of further
magnetically biased patterned second longitudinal magnetic bias
layers 24a" and 24b" having a further magnetized second magnetic
bias field strength in the second magnetic bias direction and
greater than the second magnetic bias field strength.
Within the preferred embodiment of the present invention with
respect to the third thermal annealing method, the third thermal
annealing method preferably employs a third thermal annealing
temperature of at least about 250 degrees centigrade and preferably
from about 250 to about 300 degrees centigrade and a third thermal
exposure time of at least about 3 hours, preferably from about 4 to
about 10 hours.
Referring now to FIG. 5b, there is shown a schematic perspective
view diagram corresponding with the schematic air bearing surface
(ABS) view diagram of FIG. 5a. Shown in FIG. 5b is the patterned
first magnetoresistive (MR) layer 16 having formed upon a pair of
its opposite ends the pair of remagnetized partially demagnetized
magnetically biased patterned first longitudinal magnetic bias
layers 18a'" and 18b'". Similarly, there is also shown within FIG.
5b the patterned second magnetoresistive layer 22 having formed and
aligned upon a pair of its opposite ends the pair of further
magnetically biased patterned second longitudinal magnetic bias
layers 24a" and 24b41. As is illustrated within the schematic
perspective view diagram of FIG. 5b, the pair of remagnetized
partially demagnetized magnetically biased patterned first
longitudinal magnetic bias layers 18a'" and 18b'" is remagnetized
with a remagnetized partially demagnetized first magnetic bias
field strength in the first magnetic bias direction and greater
than the partially demagnetized first magnetic bias field strength
of the pair of partially demagnetized magnetically biased patterned
first longitudinal magnetic bias layers 18a" and 18b" as is
illustrated in the schematic perspective view diagram of FIG. 4b.
Similarly, the further magnetically biased patterned second
longitudinal magnetic bias layers 24a" and 24b" are, as illustrated
within the schematic perspective view diagram of FIG. 5b, further
magnetized in the second magnetic bias direction with a further
magnetized second magnetic bias field strength greater than the
second magnetic bias field strength of the pair of magnetically
biased patterned second longitudinal magnetic bias layers 24a' and
24b' as illustrated within the schematic perspective view diagram
of FIG. 4b. All other layers within the merged inductive magnetic
write dual stripe magnetoresistive (DSMR) read magnetoresistive
(MR) sensor element whose schematic air bearing surface (ABS) view
diagram is illustrated in FIG. 5a have been omitted for
clarity.
Referring now to FIG. 6, there is shown a schematic air bearing
surface (ABS) view diagram illustrating the results of further
processing of the merged inductive magnetic write dual stripe
magnetoresistive (MR) read magnetoresistive (MR) sensor element
whose schematic air bearing surface (ABS) view diagram is
illustrated in FIG. 5a.
Shown in FIG. 6 is a schematic air bearing surface (ABS) view
diagram of a merged inductive magnetic write dual stripe
magnetoresistive (DSMR) read magnetoresistive (MR) sensor element
otherwise equivalent to the merged inductive magnetic write dual
stripe magnetoresistive (DSMR) read magnetoresistive (MR) sensor
element whose schematic air bearing surface (ABS) view diagram is
illustrated in FIG. 5a, but wherein: (1) there is formed upon the
pair of further magnetically biased patterned second longitudinal
magnetic bias layers 24a" and 24b" and the second trackwidth TW2 of
the patterned second magnetoresistive layer 22 a blanket third
non-magnetic spacer layer 26; (2) there is formed upon the blanket
third non-magnetic spacer layer 26 a blanket second shield layer 28
which simultaneously serves as a blanket first magnetic inductor
write pole layer; (3) there is formed upon the blanket second
shield layer 28 a blanket fourth non-magnetic write gap filling
spacer layer 30; and (4) there is formed upon the blanket fourth
non-magnetic write gap filling spacer layer 30 a patterned second
magnetic inductor write pole layer 32.
Within the preferred embodiment of the present invention, the
blanket third non-magnetic spacer layer 26 is preferably formed
employing methods, materials and dimensions analogous or equivalent
to the methods, materials and dimensions employed for forming the
blanket first non-magnetic spacer layer 14. Similarly, within the
preferred embodiment of the present invention the blanket second
shield layer 28 is preferably formed employing methods, materials
and dimensions analogous or equivalent to the methods, materials
and dimensions employed for forming the blanket first shield layer
12. Yet similarly, for the preferred embodiment of the present
invention, the blanket fourth non-magnetic write gap filling spacer
layer 30 is preferably formed employing methods and materials
analogous or equivalent to the methods and materials employed for
forming the blanket third non-magnetic spacer layer 26, the blanket
second non-magnetic spacer layer 20 and the blanket first
non-magnetic spacer layer 14. Preferably, the blanket fourth
non-magnetic write gap filling spacer layer 30 is formed to a
thickness of from about 500 to about 3000 angstroms of an aluminum
oxide non-magnetic dielectric spacer material. Finally, within the
preferred embodiment of the present invention, the patterned second
magnetic inductor write pole layer 32 is preferably formed
employing methods materials and thickness dimensions analogous or
equivalent to the methods, materials and thickness dimensions
employed for forming the blanket second shield layer 28, but of a
narrower width dimension in the range of from about 0.1 to about 3
microns to correspond with the first trackwidth TW1 of the
patterned first magnetoresistive layer 16 and the second trackwidth
TW2 of the patterned second magnetoresistive (MR) layer 22.
Upon forming the merged inductive magnetic write dual stripe
magnetoresistive (DSMR) read magnetoresistive (MR) sensor element
whose schematic air bearing surface (ABS) view diagram is
illustrated in FIG. 6, there is formed a merged inductive magnetic
write dual stripe magnetoresistive (DSMR) read magnetoresistive
(MR) sensor element with enhanced magnetic bias profile uniformity
within the trackwidth of the merged inductive magnetic write dual
stripe magnetoresistive (DSMR) read magnetoresistive (MR) sensor
element. The merged inductive magnetic write dual stripe
magnetoresistive (MR) read magnetoresistive (MR) sensor element of
the present invention realizes the foregoing object by employing an
anti-parallel longitudinal magnetic biasing of two pair of
patterned longitudinal magnetic biasing layers which longitudinally
magnetically bias a pair of patterned magnetoresistive (MR) layers
within the merged inductive magnetic write dual stripe
magnetoresistive (DSMR) read magnetoresistive (MR) sensor element.
The two of pair patterned longitudinal magnetic biasing layers are
preferably although not necessarily formed of a single longitudinal
magnetic biasing material. Similarly, the method of the present
invention employs when forming a pair of magnetically biased
patterned second longitudinal magnetic bias layers upon a patterned
second magnetoresistive (MR) layer a two step thermal annealing
method comprising: (1) a first thermal annealing method employing a
first thermal annealing temperature, a first thermal annealing
exposure time and a first an extrinsic magnetic bias field strength
such that a pair of magnetically un-biased patterned second
longitudinal magnetic bias layers is longitudinally magnetically
biased while de-magnetizing a pair of magnetically biased patterned
first longitudinal magnetic bias layers which longitudinally
magnetically bias a patterned first magnetoresistive (MR) layer in
a direction anti-parallel to the patterned second magnetoresistive
(MR) layer; and (2) a second thermal annealing method employing a
second thermal annealing temperature and a second thermal annealing
exposure time without a second extrinsic magnetic bias field to
further magnetize the pair of magnetically biased patterned second
magnetic bias layers when forming a pair of further magnetically
biased patterned second magnetic bias layers and remagnetize the
pair of partially demagnetized magnetically biased patterned first
longitudinal magnetic bias layers when forming a pair of
remagnetized partially demagnetized patterned first longitudinal
magnetic bias layers.
EXAMPLE
In order to illustrate the value and operation of the present
invention, there was fabricated a non-parallel anti-parallel
longitudinally magnetically biased dual stripe magnetoresistive
(DSMR) sensor element in accord with the preferred embodiment of
the present invention. The anti-parallel longitudinally
magnetically biased dual stripe magnetoresistive (DSMR) sensor
element employed a patterned first magnetoresistive (MR) layer and
a patterned second magnetoresistive (MR) layer each formed of a
nickel-iron (80:20; w/w) permalloy magnetoresistive (MR) material
formed to a thickness of about 100 angstroms, a length (long axis)
of about 0.8 microns and a width (short axis) of about 0.4 microns,
where the patterned first magnetoresistive (MR) layer had formed
upon a pair of its opposite ends separated by the long axis a pair
of magnetically un-biased patterned first longitudinal magnetic
bias layers and the patterned second magnetoresistive (MR) layer
had formed upon a pair of its opposite ends separated by the long
axis a pair of magnetically un-biased patterned second longitudinal
magnetic bias layers. Both the pair of magnetically un-biased
patterned first longitudinal magnetic bias layers and the pair of
magnetically un-biased pattern ed second longitudinal magnetic bias
layers were formed of a nickel-manganese (50:50; w/w)
antiferromagnetic longitudinal magnetic bias material formed to a
thickness of about 300 angstroms and positioned to provide a
trackwidth of the patterned first magnetoresistive (MR) layer or
the patterned second magnetoresistive (MR) layer of about 0.8
microns.
In accord with the preferred embodiment of the present invention,
the pair of magnetically un-biased patterned first longitudinal
magnetic bias layers was magnetically biased to form therefrom a
pair of magnetically biased patterned first longitudinal magnetic
bias layers prior to forming upon the patterned second
magnetoresistive (MR) layer the pair of magnetically un-biased
patterned second longitudinal magnetic bias layers, through thermal
annealing while employing a first thermal annealing method
employing a first thermal annealing temperature of about 300
degrees centigrade, a first thermal annealing exposure time of
about 8 hours and a first magnetic bias field strength of about
2000 oersteds directed at an acute angle of about 30 degrees with
respect to the long (i.e. easy) axis of either the patterned first
magnetoresistive (MR) layer or the patterned second
magnetoresistive (MR) layer. After the first thermal annealing,
measurements of: (1) an exchange bias field, Hex, between the
patterned first magnetoresistive (MR) layer and the magnetically
biased patterned first longitudinal magnetic bias layers; and (2)
coercivity field, Hc, of the patterned first magnetoresistive (MR)
layer were obtained employing methods as are conventional in the
art of magnetoresistive (MR) sensor element fabrication.
After forming the pair of magnetically un-biased patterned second
longitudinal magnetic bias layers upon the pair of opposite ends of
the patterned second magnetoresistive (MR) layer, there was then
thermally annealed the dual stripe magnetoresistive (DSMR) sensor
element while employing a second thermal annealing method which
employed a second thermal annealing temperature of about 270
degrees centigrade, a second thermal annealing exposure time of
about 0.5 hours and a second extrinsic magnetic bias field strength
of about 2000 oersteds directed anti-parallel to the first
extrinsic magnetic bias field direction, which second thermal
annealing: (1) partially demagnetized the pair of magnetically
biased patterned first magnetic bias layers to form a corresponding
pair of partially demagnetized magnetically biased patterned first
magnetic bias layers; and (2) magnetized the pair of magnetically
un-biased patterned second magnetic bias layer to form a
corresponding pair of magnetically biased patterned second magnetic
bias layers. There was then measured: (1) a first exchange field,
Hex, strength between the pair of partially demagnetized
magnetically biased patterned first longitudinal magnetic bias
layers and the patterned first magnetoresistive (MR) layer; (2) a
first coercivity field, Hc, of the patterned first magnetoresistive
(MR) layer; (3) a second exchange field, Hex, strength between the
pair of magnetically biased patterned second longitudinal magnetic
bias layers and the patterned second magnetoresistive (MR) layer;
and (4) a second coercivity field, Hc, of the patterned second
magnetoresistive (MR) layer.
There was then thermally annealed the dual stripe magnetoresistive
(DSMR) sensor element while employing a third thermal annealing
method employing a third thermal annealing temperature of about 300
degrees centigrade for a third thermal annealing time period of
about 0.5 hours in absence of a third extrinsic magnetic bias field
to: (1) form from the partially demagnetized magnetically biased
patterned first longitudinal magnetic bias layers a pair of
remagnetized partially demagnetized patterned first longitudinal
magnetic bias layers; and (2) form from the pair of magnetically
biased patterned second longitudinal magnetic bias layers a pair of
further magnetically biased patterned second longitudinal magnetic
bias layers. There was then again measured: (1) a first exchange
field, Hex, strength between the pair of remagnetized partially
demagnetized magnetically biased patterned first longitudinal
magnetic bias layers and the patterned first magnetoresistive (MR)
layer; (2) a first coercivity field, Hc, of the patterned first
magnetoresistive (MR) layer; (3) a second exchange field, Hex,
strength between the pair of further magnetically biased patterned
second longitudinal magnetic bias layers and the patterned second
magnetoresistive (MR) layer; and (4) a second coercivity field, Hc,
of the patterned second magnetoresistive (MR) layer.
Measured results for the exchange field, Hex, strengths and the
coercivity field, Hc, strengths, as defined above, are reported
within Table I, as follows.
TABLE I Annealing Conditions Hex (Oe) Hc (Oe) Hex/Hc For First
Magnetoresistive (MR) Layer 1.sup.st - 300 C./8 hr/2000 Oe 210 90
2.3 2.sup.nd - 270 C./0.5 hr/-2000 Oe 50 90 0.6 3.sup.rd - 300
C./0.5 hr/0.0 Oe 170 90 1.9 For Second Magnetoresistive (MR) Layer
2.sup.nd - 270 C./0.5 hr/-2000 Oe -20 60 -0.3 3.sup.rd - 300 C./0.5
hr/0.0 Oe -130 100 -1.3
As is seen from review of the data reported within Table I, there
is observed, in accord with that which is disclosed within the
preferred embodiment of the present invention and claimed within
the claims which follow: (1) a significant recovery of
demagnetization of an exchange bias field for a pair of partially
demagnetized magnetically biased patterned first longitudinal
magnetic bias layers with respect to a patterned first
magnetoresistive (MR) layer; and (2) an additional exchange biasing
of a pair of magnetically biased patterned second longitudinal
magnetic bias layers with respect to a patterned second
magnetoresistive (MR) layer, when an anti-parallel magnetic biased
dual stripe magnetoresistive (DSMR) sensor element having formed
therein the pair of partially demagnetized patterned first
longitudinal magnetic bias layers and the pair of magnetically
biased patterned second magnetic bias layers is thermally annealed
absent an extrinsic magnetic bias field.
As is understood by a person skilled in the art, the preferred
embodiment and example of the present invention are illustrative of
the present invention rather than limiting of the present
invention. Revisions and modifications may be made to materials,
structures and dimensions through which is provided a non-parallel
magnetically biased multiple magnetoresistive (MR) layer
magnetoresistive (MR) sensor element such as the dual stripe
magnetoresistive (DSMR) sensor element formed in accord with the
preferred embodiment of the present invention while still providing
a non-parallel magnetically biased multiple magnetoresistive (MR)
layer magnetoresistive (MR) sensor element in accord with the
spirit and scope of the present invention, as defined by the
following claims.
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